1. Field of Invention
The present invention relates to a digital camera and a method for automatically retracting its lens, and more particularly to a digital camera that can determine whether a lens needs to be automatically retracted by comparing previous and current image characteristic values, and a method for automatically retracting the lens.
2. Related Art
As the fashion develops, recently almost all the unprofessional digital cameras tend to be light, thin, short and small, and the design becomes more and more beautiful. These digital cameras have a same characteristic that they can make people capture the digital images with approximately high quality in the simplest operation.
In order to simplify the operation, almost all these unprofessional digital cameras are provided with an automatically extendable/retractable lens, so that the lens can be automatically extended for users to take pictures immediately at the same time when a user press a switch to start the digital camera. When the use of the digital camera is finished, the user only needs to press again the switch, the lens can be automatically retracted and meanwhile the power can be turned off. However, when the digital camera is in a start-up state, the lens would normally keep a state of extending out of the body of the digital camera. Although some digital cameras provide a so-called automatic stand-by function, so that the lens can be automatically retracted and the digital camera can be turned off when a user does not have any operation after the camera is turned on for a while, the lens exposed outside of the digital camera is still under a high risk of being easily damaged after the digital camera is turned on but yet reaches the automatic stand-by time.
This high risk is due to improper holding of the camera by the user, and thus situations of falling or shaking of the camera occur. All these situations can cause damage to the lens of the digital camera and make it unusable or affect the quality of a photographic image because the lens might hit or rub against the ground or other rigid articles. In fact, a lens of a digital camera is comparable to the eyes, the window of soul, of a man, and if any damage occurs to the lens, the digital camera would be almost unusable. Accordingly, a lens is usually the most expensive part in a digital camera.
Therefore, how to protect a lens at any time after a digital camera is turned on and reduce damage to the lens due to unintended falling or improper shaking of the digital camera, is an important subject urgently needed to be overcome in the present smart mechanism development of digital cameras.